Display devices including memories each arranged for each respective pixel in the display area are known. Display devices of this type write a digital signal according to an image to be displayed to each respective memory and supply a voltage corresponding to the digital signal stored in each respective memory to each respective pixel, thereby displaying the image on the display area. Such a system is called, for example, the digital mode.
A display device of the digital mode requires a switching element used for a memory device, a switching element for writing a digital signal to a memory device, and a switching element for selecting a signal to be supplied to a pixel electrode, and the like. When all of these switching elements are used formed from CMOS transistors, the number of transistors required for the circuits increases extremely. As a result, it is difficult to further improve the definition of the display device.